1. Technical Field
This invention relates to producing power, and more particularly, to a method of and apparatus for producing power in connection with the production of cement.
2. Background of the Invention
Recently, the need to produce electricity and power from local available heat sources has become of greater interest. In particular, such a heat source exists in cement producing plants. Since the environmental requirements such cement producing plants have to comply with can be quite stringent, the production of electricity and power from cement producing factories needs particular attention.
It is therefore an object of the present invention to provide a new and improved method of and apparatus for producing power wherein the disadvantages as outlined are reduced or substantially overcome.
A method for producing power, in accordance with the present invention, comprises the steps of: supplying clinker from cement production apparatus to a grate cooler for cooling the clinker; and extracting hot air from the grate cooler and supplying it to a filter e.g. an electrostatic precipitator or bag filter. When an electrostatic precipitator is used for extracting particulate matter from the hot air from the grate cooler, this hot air is supplied to the electrostatic precipitator. Thereafter, the filtered air exiting the electrostatic precipitator is supplied to an air-heat transfer fluid heat-exchanger containing e.g. thermal oil, etc., for heating the heat transfer fluid. A working fluid is vaporized using heat in the heated heat transfer fluid and vaporized working fluid and heat depleted heat transfer fluid are produced. Heat in the heat depleted heat transfer fluid is used to pre-heat working fluid, while the vaporized working fluid produced in the vaporizer is supplied to a turbine for producing power. Vaporized working fluid exiting the turbine is supplied to a working fluid condenser that condenses the vaporized working fluid exiting the turbine and produces working fluid condensate that is supplied to the vaporizer. Preferably, the method includes supplying the vaporized working fluid exiting the turbine to a recuperator that heats working fluid condensate supplied from the working fluid condenser prior to supplying said working fluid condensate to said vaporizer. Furthermore, preferably, the working fluid condensate is supplied to a pre-heater that preheats the working fluid condensate and produces preheated working fluid that is supplied to said vaporizer.
Moreover, the present invention includes apparatus for producing power comprising: a grate cooler for cooling clinker supplied from cement production apparatus; a filter e.g. an electrostatic precipitator or bag filter that extracts particulate matter from hot air supplied from said grate cooler; and an air-heat transfer fluid heat-exchanger containing e.g. thermal oil, etc., that heats said heat transfer fluid with heat from the filtered air exiting the electrostatic precipitator when such a precipitator is used. In addition, the apparatus includes a vaporizer that vaporizes working fluid using heat in the heated heat transfer fluid and produces vaporized working fluid and heat depleted heat transfer fluid. Furthermore, the apparatus includes a pre-heater that preheats working fluid using heat in said heat depleted heat transfer fluid and a turbine that receives vaporized working fluid produced in said vaporizer and produces power. The apparatus also provides a working fluid condenser that receives vaporized working fluid exiting the turbine and condenses the vaporized working fluid exiting the turbine, producing working fluid condensate that is supplied to said vaporizer. Preferably, the apparatus additionally includes a recuperator that heats working fluid condensate supplied from the working fluid condenser with heat from the vaporized working fluid exiting said turbine prior to supplying working fluid condensate to the vaporizer. Moreover, preferably, the apparatus includes a separate pre-heater that preheats the working fluid condensate and produces preheated working fluid that is supplied to the vaporizer. In the preferred embodiment of the present invention, the working fluid comprises an organic working fluid. Most preferably, the organic working fluid comprises pentane.